package com.itheima.utils;

import javax.servlet.http.HttpServletRequest;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

public class YzmUtil{



    /**
     *  获取图片对象
     *
     * @param request request对象 用来获取session对象，将验证码存储到session中
     *
     * @throws IOException
     */
    public static BufferedImage getBufferedImage(HttpServletRequest request) throws IOException {

        int width = 150;
        int height = 50;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

        Graphics g = image.getGraphics();
        g.setColor(getRandColor(200, 250));
        g.fillRect(0, 0, width, height);
        g.setColor(new Color(102, 102, 102));
        g.drawRect(20, 30, width - 20, height - 30);
        g.setFont(new Font("Times New Roman", Font.PLAIN, 40));
        g.setColor(getRandColor(160, 200));
        Random RANDOM = new Random();
        // // 画随机线
        for (int i = 0; i < 155; i++) {
            int x = 5 + RANDOM.nextInt(width - 10);
            int y = 5 + RANDOM.nextInt(height - 10);
            int xl = RANDOM.nextInt(6) + 5;
            int yl = RANDOM.nextInt(12) + 5;
            g.drawLine(x, y, x + xl, y + yl);
        }
        // // 从另一方向画随机线
        for (int i = 0; i < 70; i++) {
            int x = 5 + RANDOM.nextInt(width - 10);
            int y = 5 + RANDOM.nextInt(height - 10);
            int xl = RANDOM.nextInt(12) + 5;
            int yl = RANDOM.nextInt(6) + 5;
            g.drawLine(x, y, x - xl, y - yl);
        }
        // 生成随机数,并将随机数字转换为字母
        String code = "";
        for (int i = 0; i < 4; i++) {
            int itmp = RANDOM.nextInt(26) + 65;
            char ctmp = (char) itmp;
            code += String.valueOf(ctmp);
            g.setColor(new Color(20 + RANDOM.nextInt(110), 20 + RANDOM.nextInt(110), 20 + RANDOM.nextInt(110)));
            g.drawString(String.valueOf(ctmp), 25 * i + 20, 40);
        }
        g.dispose();

        //接收随机生成的code
        request.getSession().setAttribute("yzmCode", code);
        return image;
    }

    /**
     * 给定范围获得随机颜色
     * @param fc
     * @param bc
     * @return
     */
    static Color getRandColor(int fc, int bc) {
        Random random = new Random();
        if (fc > 255){
            fc = 255;
        }
        if (bc > 255){
            bc = 255;
        }
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }


}
